From: Bjorn Helgaas <helgaas@kernel.org> To: Lianbo Jiang <lijiang@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com>, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, akpm@linux-foundation.org, dan.j.williams@intel.com, thomas.lendacky@amd.com, baiyaowei@cmss.chinamobile.com, tiwai@suse.de, bp@suse.de, brijesh.singh@amd.com, dyoung@redhat.com, bhe@redhat.com Subject: [PATCH 3/3] resource: Fix find_next_iomem_res() iteration issue Date: Mon, 24 Sep 2018 17:15:03 -0500 [thread overview] Message-ID: <153782730364.130337.17794279728329113665.stgit@bhelgaas-glaptop.roam.corp.google.com> (raw) In-Reply-To: <153782698067.130337.12079523922130875402.stgit@bhelgaas-glaptop.roam.corp.google.com> From: Bjorn Helgaas <bhelgaas@google.com> Previously find_next_iomem_res() used "*res" as both an input parameter for the range to search and the type of resource to search for, and an output parameter for the resource we found, which makes the interface confusing and hard to use correctly. All callers allocate a single struct resource and use it for repeated calls to find_next_iomem_res(). When find_next_iomem_res() returns a resource, it overwrites the start, end, flags, and desc members of the struct. If we call find_next_iomem_res() again, we must update or restore these fields. The callers (__walk_iomem_res_desc() and walk_system_ram_range()) do not restore res->flags, so if the caller is searching for flags of IORESOURCE_MEM | IORESOURCE_BUSY and finds a resource with flags of IORESOURCE_MEM | IORESOURCE_BUSY | IORESOURCE_SYSRAM, the next search will find only resources marked as IORESOURCE_SYSRAM. Fix this by restructuring the interface so it takes explicit "start, end, flags" parameters and uses "*res" only as an output parameter. Original-patch: http://lore.kernel.org/lkml/20180921073211.20097-2-lijiang@redhat.com Based-on-patch-by: Lianbo Jiang <lijiang@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> --- kernel/resource.c | 94 +++++++++++++++++++++++------------------------------ 1 file changed, 41 insertions(+), 53 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index 155ec873ea4d..9891ea90cc8f 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -319,23 +319,26 @@ int release_resource(struct resource *old) EXPORT_SYMBOL(release_resource); /* - * Finds the lowest iomem resource existing within [res->start..res->end]. - * The caller must specify res->start, res->end, res->flags, and optionally - * desc. If found, returns 0, res is overwritten, if not found, returns -1. - * This function walks the whole tree and not just first level children until - * and unless first_level_children_only is true. + * Finds the lowest iomem resource that covers part of [start..end]. The + * caller must specify start, end, flags, and desc (which may be + * IORES_DESC_NONE). + * + * If a resource is found, returns 0 and *res is overwritten with the part + * of the resource that's within [start..end]; if none is found, returns + * -1. + * + * This function walks the whole tree and not just first level children + * unless first_level_children_only is true. */ -static int find_next_iomem_res(struct resource *res, unsigned long desc, - bool first_level_children_only) +static int find_next_iomem_res(resource_size_t start, resource_size_t end, + unsigned long flags, unsigned long desc, + bool first_level_children_only, + struct resource *res) { - resource_size_t start, end; struct resource *p; bool sibling_only = false; BUG_ON(!res); - - start = res->start; - end = res->end; BUG_ON(start >= end); if (first_level_children_only) @@ -344,7 +347,7 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, read_lock(&resource_lock); for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) { - if ((p->flags & res->flags) != res->flags) + if ((p->flags & flags) != flags) continue; if ((desc != IORES_DESC_NONE) && (desc != p->desc)) continue; @@ -359,32 +362,31 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, read_unlock(&resource_lock); if (!p) return -1; + /* copy data */ - if (res->start < p->start) - res->start = p->start; - if (res->end > p->end) - res->end = p->end; + res->start = max(start, p->start); + res->end = min(end, p->end); res->flags = p->flags; res->desc = p->desc; return 0; } -static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, - bool first_level_children_only, - void *arg, +static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end, + unsigned long flags, unsigned long desc, + bool first_level_children_only, void *arg, int (*func)(struct resource *, void *)) { - u64 orig_end = res->end; + struct resource res; int ret = -1; - while ((res->start < res->end) && - !find_next_iomem_res(res, desc, first_level_children_only)) { - ret = (*func)(res, arg); + while (start < end && + !find_next_iomem_res(start, end, flags, desc, + first_level_children_only, &res)) { + ret = (*func)(&res, arg); if (ret) break; - res->start = res->end + 1; - res->end = orig_end; + start = res.end + 1; } return ret; @@ -407,13 +409,7 @@ static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; - - res.start = start; - res.end = end; - res.flags = flags; - - return __walk_iomem_res_desc(&res, desc, false, arg, func); + return __walk_iomem_res_desc(start, end, flags, desc, false, arg, func); } EXPORT_SYMBOL_GPL(walk_iomem_res_desc); @@ -427,13 +423,9 @@ EXPORT_SYMBOL_GPL(walk_iomem_res_desc); int walk_system_ram_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; - - res.start = start; - res.end = end; - res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true, + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true, arg, func); } @@ -444,13 +436,9 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, int walk_mem_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; - - res.start = start; - res.end = end; - res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; + unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY; - return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true, + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true, arg, func); } @@ -464,25 +452,25 @@ int walk_mem_res(u64 start, u64 end, void *arg, int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, void *arg, int (*func)(unsigned long, unsigned long, void *)) { + resource_size_t start, end; + unsigned long flags; struct resource res; unsigned long pfn, end_pfn; - u64 orig_end; int ret = -1; - res.start = (u64) start_pfn << PAGE_SHIFT; - res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; - res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - orig_end = res.end; - while ((res.start < res.end) && - (find_next_iomem_res(&res, IORES_DESC_NONE, true) >= 0)) { + start = (u64) start_pfn << PAGE_SHIFT; + end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; + flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + while (start < end && + !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, + true, &res)) { pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT; end_pfn = (res.end + 1) >> PAGE_SHIFT; if (end_pfn > pfn) ret = (*func)(pfn, end_pfn - pfn, arg); if (ret) break; - res.start = res.end + 1; - res.end = orig_end; + start = res.end + 1; } return ret; }
WARNING: multiple messages have this Message-ID (diff)
From: Bjorn Helgaas <helgaas@kernel.org> To: Lianbo Jiang <lijiang@redhat.com> Cc: dan.j.williams@intel.com, brijesh.singh@amd.com, bhe@redhat.com, thomas.lendacky@amd.com, tiwai@suse.de, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, mingo@redhat.com, baiyaowei@cmss.chinamobile.com, hpa@zytor.com, tglx@linutronix.de, bp@suse.de, dyoung@redhat.com, akpm@linux-foundation.org, Vivek Goyal <vgoyal@redhat.com> Subject: [PATCH 3/3] resource: Fix find_next_iomem_res() iteration issue Date: Mon, 24 Sep 2018 17:15:03 -0500 [thread overview] Message-ID: <153782730364.130337.17794279728329113665.stgit@bhelgaas-glaptop.roam.corp.google.com> (raw) In-Reply-To: <153782698067.130337.12079523922130875402.stgit@bhelgaas-glaptop.roam.corp.google.com> From: Bjorn Helgaas <bhelgaas@google.com> Previously find_next_iomem_res() used "*res" as both an input parameter for the range to search and the type of resource to search for, and an output parameter for the resource we found, which makes the interface confusing and hard to use correctly. All callers allocate a single struct resource and use it for repeated calls to find_next_iomem_res(). When find_next_iomem_res() returns a resource, it overwrites the start, end, flags, and desc members of the struct. If we call find_next_iomem_res() again, we must update or restore these fields. The callers (__walk_iomem_res_desc() and walk_system_ram_range()) do not restore res->flags, so if the caller is searching for flags of IORESOURCE_MEM | IORESOURCE_BUSY and finds a resource with flags of IORESOURCE_MEM | IORESOURCE_BUSY | IORESOURCE_SYSRAM, the next search will find only resources marked as IORESOURCE_SYSRAM. Fix this by restructuring the interface so it takes explicit "start, end, flags" parameters and uses "*res" only as an output parameter. Original-patch: http://lore.kernel.org/lkml/20180921073211.20097-2-lijiang@redhat.com Based-on-patch-by: Lianbo Jiang <lijiang@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> --- kernel/resource.c | 94 +++++++++++++++++++++++------------------------------ 1 file changed, 41 insertions(+), 53 deletions(-) diff --git a/kernel/resource.c b/kernel/resource.c index 155ec873ea4d..9891ea90cc8f 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -319,23 +319,26 @@ int release_resource(struct resource *old) EXPORT_SYMBOL(release_resource); /* - * Finds the lowest iomem resource existing within [res->start..res->end]. - * The caller must specify res->start, res->end, res->flags, and optionally - * desc. If found, returns 0, res is overwritten, if not found, returns -1. - * This function walks the whole tree and not just first level children until - * and unless first_level_children_only is true. + * Finds the lowest iomem resource that covers part of [start..end]. The + * caller must specify start, end, flags, and desc (which may be + * IORES_DESC_NONE). + * + * If a resource is found, returns 0 and *res is overwritten with the part + * of the resource that's within [start..end]; if none is found, returns + * -1. + * + * This function walks the whole tree and not just first level children + * unless first_level_children_only is true. */ -static int find_next_iomem_res(struct resource *res, unsigned long desc, - bool first_level_children_only) +static int find_next_iomem_res(resource_size_t start, resource_size_t end, + unsigned long flags, unsigned long desc, + bool first_level_children_only, + struct resource *res) { - resource_size_t start, end; struct resource *p; bool sibling_only = false; BUG_ON(!res); - - start = res->start; - end = res->end; BUG_ON(start >= end); if (first_level_children_only) @@ -344,7 +347,7 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, read_lock(&resource_lock); for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) { - if ((p->flags & res->flags) != res->flags) + if ((p->flags & flags) != flags) continue; if ((desc != IORES_DESC_NONE) && (desc != p->desc)) continue; @@ -359,32 +362,31 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, read_unlock(&resource_lock); if (!p) return -1; + /* copy data */ - if (res->start < p->start) - res->start = p->start; - if (res->end > p->end) - res->end = p->end; + res->start = max(start, p->start); + res->end = min(end, p->end); res->flags = p->flags; res->desc = p->desc; return 0; } -static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, - bool first_level_children_only, - void *arg, +static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end, + unsigned long flags, unsigned long desc, + bool first_level_children_only, void *arg, int (*func)(struct resource *, void *)) { - u64 orig_end = res->end; + struct resource res; int ret = -1; - while ((res->start < res->end) && - !find_next_iomem_res(res, desc, first_level_children_only)) { - ret = (*func)(res, arg); + while (start < end && + !find_next_iomem_res(start, end, flags, desc, + first_level_children_only, &res)) { + ret = (*func)(&res, arg); if (ret) break; - res->start = res->end + 1; - res->end = orig_end; + start = res.end + 1; } return ret; @@ -407,13 +409,7 @@ static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; - - res.start = start; - res.end = end; - res.flags = flags; - - return __walk_iomem_res_desc(&res, desc, false, arg, func); + return __walk_iomem_res_desc(start, end, flags, desc, false, arg, func); } EXPORT_SYMBOL_GPL(walk_iomem_res_desc); @@ -427,13 +423,9 @@ EXPORT_SYMBOL_GPL(walk_iomem_res_desc); int walk_system_ram_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; - - res.start = start; - res.end = end; - res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true, + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true, arg, func); } @@ -444,13 +436,9 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, int walk_mem_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; - - res.start = start; - res.end = end; - res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; + unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY; - return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true, + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true, arg, func); } @@ -464,25 +452,25 @@ int walk_mem_res(u64 start, u64 end, void *arg, int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, void *arg, int (*func)(unsigned long, unsigned long, void *)) { + resource_size_t start, end; + unsigned long flags; struct resource res; unsigned long pfn, end_pfn; - u64 orig_end; int ret = -1; - res.start = (u64) start_pfn << PAGE_SHIFT; - res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; - res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - orig_end = res.end; - while ((res.start < res.end) && - (find_next_iomem_res(&res, IORES_DESC_NONE, true) >= 0)) { + start = (u64) start_pfn << PAGE_SHIFT; + end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; + flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + while (start < end && + !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, + true, &res)) { pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT; end_pfn = (res.end + 1) >> PAGE_SHIFT; if (end_pfn > pfn) ret = (*func)(pfn, end_pfn - pfn, arg); if (ret) break; - res.start = res.end + 1; - res.end = orig_end; + start = res.end + 1; } return ret; } _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2018-09-24 22:15 UTC|newest] Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-09-21 7:32 [PATCH 0/3 v3] add reserved e820 ranges to the kdump kernel e820 table Lianbo Jiang 2018-09-21 7:32 ` Lianbo Jiang 2018-09-21 7:32 ` [PATCH 1/3 v3] resource: fix an error which walks through iomem resources Lianbo Jiang 2018-09-21 7:32 ` Lianbo Jiang 2018-09-24 17:52 ` Bjorn Helgaas 2018-09-24 17:52 ` Bjorn Helgaas 2018-09-25 7:08 ` lijiang 2018-09-25 7:08 ` lijiang 2018-09-24 22:14 ` [PATCH 0/3] find_next_iomem_res() fixes Bjorn Helgaas 2018-09-24 22:14 ` Bjorn Helgaas 2018-09-24 22:14 ` [PATCH 1/3] x86/kexec: Correct KEXEC_BACKUP_SRC_END off-by-one error Bjorn Helgaas 2018-09-24 22:14 ` Bjorn Helgaas 2018-09-24 22:14 ` [PATCH 2/3] resource: Include resource end in walk_*() interfaces Bjorn Helgaas 2018-09-24 22:14 ` Bjorn Helgaas 2018-09-24 22:15 ` Bjorn Helgaas [this message] 2018-09-24 22:15 ` [PATCH 3/3] resource: Fix find_next_iomem_res() iteration issue Bjorn Helgaas 2018-09-25 8:58 ` Baoquan He 2018-09-25 8:58 ` Baoquan He 2018-09-25 11:20 ` Baoquan He 2018-09-25 11:20 ` Baoquan He 2018-09-27 5:27 ` lijiang 2018-09-27 5:27 ` lijiang 2018-09-27 14:03 ` Bjorn Helgaas 2018-09-27 14:03 ` Bjorn Helgaas 2018-09-28 5:09 ` lijiang 2018-09-28 5:09 ` lijiang 2018-09-28 13:10 ` Borislav Petkov 2018-09-28 13:10 ` Borislav Petkov 2018-09-26 9:22 ` [PATCH 0/3] find_next_iomem_res() fixes lijiang 2018-09-26 9:22 ` lijiang 2018-09-26 13:36 ` lijiang 2018-09-26 13:36 ` lijiang 2018-09-21 7:32 ` [PATCH 2/3 v3] x86/kexec_file: add e820 entry in case e820 type string matches to io resource name Lianbo Jiang 2018-09-21 7:32 ` Lianbo Jiang 2018-09-21 7:32 ` [PATCH 3/3 v3] x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table Lianbo Jiang 2018-09-21 7:32 ` Lianbo Jiang 2018-10-16 2:56 ` [PATCH 0/3 v3] add reserved e820 ranges to the " Dave Young 2018-10-16 2:56 ` Dave Young 2018-10-16 3:45 ` lijiang 2018-10-16 3:45 ` lijiang 2018-09-27 14:21 [PATCH 0/3] find_next_iomem_res() fixes Bjorn Helgaas 2018-09-27 14:22 ` [PATCH 3/3] resource: Fix find_next_iomem_res() iteration issue Bjorn Helgaas 2018-09-27 14:22 ` Bjorn Helgaas 2018-09-28 16:41 ` Borislav Petkov 2018-09-28 16:41 ` Borislav Petkov 2018-10-09 17:30 ` Bjorn Helgaas 2018-10-09 17:30 ` Bjorn Helgaas 2018-10-09 17:35 ` Borislav Petkov 2018-10-09 17:35 ` Borislav Petkov
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